Tympanic membrane perforation (TMP, or "ruptured eardrum") is a common occurrence caused by trauma, ear infections, or pressure equalization tube insertion. TMP may cause significant hearing loss or a portal for water exposure or infection. Current treatment uses a patient's own adipose or soft tissue to provide a template for repair of the perforation, often requiring general anesthesia and associated morbidity. The total cost of all TMP treatments approaches $60 million dollars annually. A substantial number of the patients with TMP are young children, and thus a convenient in-office protocol would be highly desirable. Sentrx Surgical, Inc. is a Utah startup company formed to commercialize in situ crosslinkable glycosaminoglycan (GAG) hydrogels for ear, nose and throat (ENT) and craniofacial surgery. Sentrx Surgical will establish the feasibility of using in situ crosslinkable hyaluronan (HA) and chondroitin sulfate (CS) hydrogels to improve outcome in repair of TMP. Preliminary data using an in vivo guinea pig model of acute TMP showed a significant increase in rate of TMP repair by simple injection of a gelling mixture of chemically-modified HA. In this Phase I STTR, Sentrx Surgical will partner with U Utah to establish the chemical and biological parameters that will demonstrate feasibility for using the in situ crosslinkable HA and CS hydrogels in human patients. Specifically, we will explore three specific aims: First, we will prepare four materials to select optimal mechanical and biological properties of the in situ crosslinkable gels. Second, we will establish the in vivo efficacy of each of the four materials for TMP repair in a guinea pig model. Third, we will evaluate the biocompability and otocompability of each gel in vivo by evaluating recovery of auditory function and middle ear histology.